Apparatus for incubation cultures

ABSTRACT

THIS INVENTION COMPRISES AN INCUBATOR HAVING AN INNER CORE ASSEMBLY HAVING HORIZONTALLY EXTENDING SHELVES FOR SUPPORING CULTURE PLATES IN SEPARATED STACKED RELATIONSHIP TO PROVIDE AIR FLOW AND TEMPERATURE TRANSFER TO THE CENTER OF PLATES FROM ALL SURFACES, AND WHEREIN THE VERTICAL COLUMN OF SHELVES OF THE INNER CORE ASSEMBLY IS SUPPORTED WITHIN A SURROUNDING AND ALSO CYLINDER-LIKE OUTER CANISTER ASSEMBLY THUS PROVIDING FOR PISTON-LIKE ACTION AND TRAPPING OF THE WARM CANISTER ATMOSPHERE WITHIN THE CANISTER WHEN THE INCUBATOR IS BEING MOVED IN AN OPEN POSITION FOR ACCESSING OF AN INDIVIDUAL PLATE.

Feb. 9, 1971 R, M, STE|D| ETAL 3,562,114

APPARATUS FOR INCUBATION CULTURES Filed Jan. 5, 1970 y 5 Sheets-Sheet l Feb. 9, 1971 R M STElDL ETAL 3,562,114

APPARATUS FOR INCUBATION CULTURES Filed Jan. s, 1970 l s sheets-sheet 2 ZZ. 1:) M91 69 g (d ILL 77g V/ww 73J W2 69 75 ,qfofmw Feb. 9, 1971 R, M, STE|DL ETAL 3,562,14

APPARATUS FOR INCUBATION CULTURES Filed Jan. 5, 1970 3 Sheets-Sheet 5 Mii WM T-OENE 'Y United States Patent O 3,562,114 APPARATUS FOR INCUBATION CULTURES Richard M. Steidl, 444 Yosemite N., Minneapolis, Minn. 55422, and Robert H. Steidl, 17030 15th NW., Seattle, Wash. 98177 Filed `lan. 5, 1970, Ser. No. 716 Int. Cl. G12b 1/00 U.S. Cl. 195-139 3 Claims ABSTRACT OF THE DISCLOSURE This invention comprises an incubator having an inner core assembly having horizontally extending shelves for supporting culture plates in separated stacked relationship to provide air ow and temperature transfer to the center of plates from all surfaces, and wherein the vertical column of shelves of the inner core assembly is supported within a surrounding and also cylinder-like outer canister assembly thus providing for piston-like action and trapping of the warm canister atmosphere within the canister when the incubator is being moved into an open position for accessing of an individual plate.

This invention relates to apparatus for processing culture plates containing microorganisms under controlled conditions and more particularly to such an apparatus having improved incubation characteristics.

Cabinet model incubators in current use in research and clinical laboratories contain the culture plates in stacked relationship and as a consequence heat is transmitted to the interior of the plates principally through the edges. Such a heat flow process can thus be seen as detrimental to the maintenance of the cultures at a constant incubating temperature particularly when the cabinets are opened for accessing of a particular culture and there is a large loss of heat and drop of temperature within the incubator since the time interval between closing, reheating, and return of the culture to incubating temperature is lengthened by the lag in heat transmission through the edges of the plates, the mechanism previously mentioned which results from their stacked relationship.

While opening of a cabinet incubator results in rapid loss of incubating temperature, the Search to nd a particular culture results in further length of incubator open time and consequent heat loss since it is usually necessary to remove stacks of plates and sort them to find a particular culture even when the exact position in a lparticular stack is known and the marking of a particular culture plate alone is not relied upon.

Besides the preceding problems of finding a particular culture and maintenance of incubation conditions for the cultures, with conventional methods where high tension CO2 is desired it is necessary to rst place the culture plates within a container in which CO2 is generated by some means with the container than being subsequently placed in a cabinet incubator.

lt is, therefore, an object of this invention to provide a method and apparatus for providing access to a preselected culture plate in incubator apparatus in a minimum number of steps and with a minimum disturbance to the remaining microorganism bearing culture plates being incubated, and to provide a simple means for anerobic and CO2 incubation.

The present invention utilizes the canister concept wherein the incubator cover is attached to the inner cylinder of the core assembly holding the plates individually and separately on vertically spaced shelves so that only a single motion is required to obtain access to a preselected culture plate which is easily identified and removed without sorting or altering the position of any other plates. The piston action of the columns of plates causes the 3,562,114 Patented Feb. 9, 1971 fice heated incubator atmosphere to be trapped within the canister when the core assembly is raised to a particular open position. On closing the incubator the trapped warmed atmosphere is flushed upward along the inner wall of the outer cylinder of the canister assembly, so that the temperature within the incubator is immediately returned to present level, conserving heat and returning culture plates to incubating temperature in a much shorter time interval than with conventional cabinet models. Since in the present canister apparatus there is complete separation of any given plate from all others with air flow therebetween and consequent heat fiow to the center of the plate from all surfaces rather than from merely the edges, a serious deficiency of the presently used apparatus as hereinbefore mentioned is avoided. In the present canister system, closing the canister core cap seals the apparatus from the outside environment and a flush valve quickly adjusts the interior of the canister to the desired CO2 tension if desired. Anaerobic conditions can readily be met by connecting the outlet valve to a vacuum pump or flushing the system with nitrogen or hydrogen. An optional arrangement mounted within the canister can be provided to ignite the hydrogen to burn up any oxygen which may remain following ushing, platinized carbon devices comprising known catalyzers for the combustion of oxygen and hydrogen may be utilized for such purposes in the manner well known by those skilled in the art.

A further unique feature of the invention is the provision of a pressure lock between canister assembly and core assembly which permits locking or release by a slight rotation only of the clamping arm pivoting on the handle member of the core cap `which results in an accessing of individual plates in merely two steps with a single hand of the operator, the first comprising rotation of the clamping arm and the second simply a lift-vertically of the core assembly by its handle.

Further features of the present canister type incubator include a unique pressure indicating device indicating at a glance the pressurized status of the incubator.

The aforementioned objects and features and advantages and others of substantial importance will become readily apparent to those skilled in the art of growing cultures upon reference to the following description, when taken in conjunction with the accompanying drawings, wherein:

FIG. l is a perspective view of the canister type incubator apparatus in accordance with the present invention shown in disassembled relation;

FIG. 2 is a schematic elevation, partly in cross-section of the canister type incubator apparatus of FIG. l however shown in assembled locked relationship;

FIG. 3 is a plan section on the line 3-3 of FIG. 2 better illustrating the shelf relationship within the core Shaft;

FIG. 4 is a view as seen along the lines 4 4 of FIG. 3 showing the shelf with plate retaining means and plates in position within the canister incubator;

FIG. 5 is a plan view of the pressure locking means carried by the core cap;

FIG. 6 is an enlarged sectional view of the pressure locking means and core cap to show the various structural relationships in greater detail;

FIG. 7 is a detailed view of the pressure indicating means of the core cap.

The container structure shown in FIG. l comprises an outer canister assembly 24 and an inner core assembly 26 which is shown removed for purposes of illustration of structural features and detailed description and understanding thereof. The canister assembly 24 includes a canister shaft or tube which in the actual apparatus manufactured consists of cylinder of thermally conducting material aluminum having an outside diameter of 5.00 inches, a wall thickness of 0.06 inch, and a length of 18 inches. The cylinder 50 is supported in an upright vertical position by base member 32 which has an upper sleeve portion 33a within which cylinder 50 is tightly fitted and dixedly secured. The base member 32 includes a pilot light 28 `mounted thereon to indicate that the heating system within canister assembly 24 is operational, and a switch 30 (here illustrated as a toggle switch) to apply power and make the heating system operational. Electrical power cord 104 extends from the switch 30 to a power main and when plugged in supplies 115 volt alternating current power to the heating system by way of switch 30. A sensing platform 44 comprises a bracket extending between opposite inner walls of cylinder 50 which houses a temperature regulating means or thermostat for automatically controlling the temperature range within canister assembly 24. The temperature regulating means 42 utilized in the manufactured assembly may be an S18 type thermal switch manufactured by Standard Controls Inc. of Seattle, Wash., modied to provide an on-olf controlling range of 96 degrees plus or minus 2 degrees Fahrenheit, however the particular type of thermostat utilized will depend upon the accuracy of the limits of and extend of the range within which temperature and the controlled conditions are to be maintained and this will in turn depend upon the type of experiments or growth conditions to be achieved. Temperature regulating means 42 is centrally located on the central axis of cylinder 50 in the air space between the heater 36 and bottom shelf 97 of core assembly 26. For further reasons as will be explained later in connection with the prevention of heat spill or heat loss the heater 36 is positioned inside and at the bottom of cylinder 50. As a consequence a more accurate indication of temperature for example immediately subsequent to the closing and retum of core assembly 26 down into canister assembly results when the temperature sensing and control means 42 is located in the previously defined air space or zone intermediate heater 36 and bottom shelf 97. As seen in FIG. 2, control means 42 is shown insulatively supported from sensing platform bracket 44 by nonconductive pad member 34 which is made of berglass. Restraining rim assembly 62 includes restraining ring 64 and restraining ring tabs 66 with associated hardware 68 (bolts 69 and nut plates 70, see FIG. 2 for further details) and can be seen to provide good thermal contact and assembly between heater 36 held and clamped thereby and the inner Walls of canister shaft 50 and base plate assembly 38.

Turning now to the core assembly `26 shown on the right hand side of FIG. 1 completely removed from canister assembly 24 it can be seen that the inner core assembly 26 comprises a core cap 52 (see FIGS. 5 and 6) which includes a top plate or cover 52d having a downwardly extending cylinder wall 52a` (see FIG. 1) which houses the upper cylinder portion 48a of core shaft tube 48 therein and being permanently and iixedly secured f thereto by tight t or solder or weld or a combination thereof therebetween. Top plate or cover 52(d) has a flange 52a which extends outwardly and horizontally beyond the diameter of the vertically or downwardly extending cylinder wall portion 52C. The circular ange `52(a) has opposite ilat edges 52b formed by cut out portions on opposite sides of flange 52a, these at edges being located opposite and parallel to handle member 22 `and portions 22a. Further, the length of edges 52b is greater than the width of inturned flange portions 16C of clamping arm 16 to permit free passage upward and downward of inturned flange portions 16e during the pressure locking and unlocking for opening and closing the canister incubator. In FIG. 1 on the left side thereof it can be seen that the canister lock ring 60 includes a flange portion 60a surrounding cylinder 50 and extending outwardly therefrom the same distance from the central axis of the canister incubator as does core cap ange 52a (see FIG. 2). Edges 60b are cut out of circular lock ring llange 60a in the same manner and have the same lengths and location with respect to the center axis of the canister incubator as assembled as the edges 52b for the core cap flange 52a. Thus it can readily be seen particularly in FIGS. 2 and 6 that when the core assembly 26 is slipped into the canister assembly 24, O-ring 102 which is seated in a circular indentation in the wall of core cap cylinder S2(c) becomes seated against the inner Wall of canister shaft in the region thereof immediately behind lock ring flange portion (a).

The present canister incubator includes the unique capability of providing theV user with an apparatus which may be carried, opened with access to any single culture plate, pressure sealed and locked easily by a series of steps or motions which require the use only of a single hand thus leaving the remaining hand free and available for the removal of and/ or insertion of other culture plates. This capability is of great importance and it is believed will be greatly appreciated by those in laboratories and others who utilize extensively incubator apparatus and must handle, sort, and process many culture plates.

Upon insertion of the core assembly 26 into the canister assembly 24, the operator who had the palm placed against the top surface of the clamping arm central portion 16a and fingers under handle member 22 rotates the core cap flange guide edge 52b so that it is superposed over and in alignment with the canister lock ring guide edge 6011 directly beneath. At this time the core assembly has become seated within canister assembly 24 and it can be seen in FIG. 1 and also FIG. 2 that felt guide ring 46 which fastened around the inner surface of cylinder 50 provides a free sliding t and permits the insertion of the core assembly 26 within cylinder 50 in piston like fashion with the core shaft 48 side wall portions 48C, 48d, and back wall portion 48e forming the walls of the cylinder like core shaft 48 in contact with the aforesaid felt guide ring 46 and insuring spacing of and suspension of the core assembly 2,6 equidistantly and in an air space relationship with the inner walls of outer canister shaft cylinder 50. Such a relationship provides the equal distribution of heat along surfaces 48b, 48e and 48d of the core shaft 48 and consequent equal transmission of heat by conduction to the shelves 94, 96, 97, 98 and 99 which are horizontally extending and supported by downturned end portions or ilanges 106 which are fastened to the surfaces 48b, 48e and 48d by any well known technique such as soldering or welding. Uneven heat conduction to the various shelves which are distributed different distances from the heating means by means of the outer walls is not relied upon as the exclusive heat transmitting mechanism. With the core assembly 26 now suspended and supported by the canister assembly 24 and the O-ring 102 which may be of compressible rubber now compressed between core cap cylinder 52C and the inner wall of cylinder 50, an effective seal is made therebetween so that the atmosphere provided for and conditioned within the canister incubator may be quickly established and maintained within the desired limits of temperature and pressure. The operator then presses the palm downward on the outer surface and central portion 16a of clamping arm 16 urging movable clamping arm 16 which is pivoted on handle 22 by support pin 18 downward against the counteracting forces of torsion spring 12 which is wound around pin 18 and anchored at the upper end thereof to the side of clamping arm central portion 16a by an upward twist thereof and direct contact therewith as can be seen in FIGS. 5 and 6. It should be noted that tension spring 12 keeps the clamping arm twisted around into locked position in which case the central portion 16a is not aligned with its longitudinal axis in parallel with and directly above the longitudinal axis but is counterclockwise thereof as shown in dotted line form in FIG. 5 and again in FIG. 1 (right hand side thereof). When applying pressure with the palm of the hand the operator also urges as by thumb and little finger clamping arm 16 downward but urging it into parallel relationship with a directly above the handle member 22 (see FIG. 5 as shown with downturned flange portion 16b passing downward and opposite core cap flange guide 52b). Only a slight rotation now by the operator of the clamping arm 16 in a clockwise direction away from its parallel relationship above handle member 22 allows locking since the inturned flange portions 16C are now permitted to rotate into position under the lock ring region of decreased thickness 6012 (see FIG. 1) and the upper surface of inturned flange portions 16C rests against the bottom surface of lock ring 60 in the slot formed under the region of decreased thickness 60b. Reference to FIG. 2 shows inturned flange 16C locked in position under this locking region 6011 preventing unsealing of the canister incubator by pressure of the gas from within. The distance between the ends of inturned flange portions 16C is less than the outer diameter of lock ring flange portion 60a. The same structural features for locking are provided at opposite sides of the canister incubator for each end of the clamping arm 16. A slight twist of clamping arm 16 in the opposite direction (counterclockwise) disengages inturned flange 16 from under the decreased thickness region 60b forming the locking slot in canister lock ring 60 and permits clamping arm to pop up under the influence of torsion spring 12 thus withdrawing inturned flange portions 16e above canister lock ring 60 and permitting upward withdrawal of the core assembly 26 in piston like fashion from the canister assembly 24 to the extent necessary to remove a culture plate from its assigned shelf position.

The special nature and characteristics of the shelves 94, 97, 98, and 99 and core shaft 48 will be understood when reference is made to FIGS. 3 and 4 where it can be seen that each shelf, e.g. 94 is generally T-shaped with the ends of the T comprising downturned flange portions secured to the core assembly by means known in the art. The top edge of the T shown at 94a in FIG. 3 constitutes the front edge of the shelf over which is passed a culture plate 80 to be supported by shelf 94. As the plate is inserted the retainer spring 92 xed at bonding region 96 to the bottom of the shelf above clips and retains the culture plate 80 thus preventing it from moving away to the sides of the shelf. The T-shaped nature of shelf 94 permits ease of insertion and withdrawal of culture plate 80 since the culture plate 80 when inserted and retained as shown in FIG. 3 still extends outward beyond the edge 94a of the shelf thus permitting easy grasping thereof. The T-shape nature of shelf 94 also permits uniform conduction of heat from core shaft 48 since conductivity coupled at opposite core shaft side walls 48e and 48d and also to core shaft back wall 48e. The T-shape nature of shelf 94 while permitting uniform conduction of heat from core shaft 48 also permits maximum transmission of heat from heating means 36 to the culture plate 80 because T-shelf construction minimizes shelf area and permits flow of heat by the air or particular gas up through the canister incubator without tiered shelf obstruction to the heated air. T-shelf construction also prevents a lifting out of heated air by the shelves when the core assembly 26 is lifted for access to a particular culture plate. On closing the incubator the warm air is flushed upward along the inner wall of the canister and is not impeded by larger shelf areas than required to retain the culture' plates, so that temperature within the incubator returns to preset level, conserving heat and returning culture plates to incubating temperature in much shorter time interval than with conventional cabinet models.

A purge valve located in top plate or cover 52d may be a type A-4P-2 manufactured by Automation Products of Seattle, Wash., however other release valves may be selected and substituted therefor depending upon the particular application. A check valve 40 mounted in the wall of canister shaft 50 may be a type A-4C-l/ 3 manufactured by Automation Products of Seattle, Wash. or other type inlet valve may be selected as desired.

A further feature of importance of the core assembly 26 which should be noted concerns core shaft lower cylinder portion -48b -which extends around and concentrically within and spaced from the inner wall of canister cylinder 50. This lower extension of the core assembly channels heat flowing from the heater 36 below upward along the edges of the culture plates protruding beyond the edges of the shelves and also collects heat for transmission by conduction along core shaft side Walls 48C, y48d and core shaft back wall 48e to the shelves and plates thereon. Maximum and eilicient utilization of heat by conduction and convection is provided for the circular shaped culture plates positioned on and having edges extending into the canister incubator air space beyond the T shaped supporting shelves.

Indicator means (see FIG. 7 for details thereof) for showing the condition of pressurization of the canister by a simply constructed pressure indicator member 54 of solid red plastic of rigid nature in the form of a plug with a top cylindrically shaped upper portion 54a of diameter less than the core cap aperture 56 through which it is forced upward to protrude through when the pressure on pressure sensor membrane 58 of latex is sufficient to when urged against its base cylindrical portion 54b provide the necessary upward force. Membrane 58 is stretched across a ridge 108 extending downward from top plate 52d beyond the perimeter of core cap aperture 56. Other more precise pressure indicating means could be incorporated where the metered gas pressure is not known, however the present simple structured means provides the desired quick indication of pressurized status of the canister incubator. Ballast member 72 (of cast iron) for stabilizing the canister incubator is supported within base member 32 by hardware which includes No. 1'0 nut plates 74 and seven eighths inch No.

10 screws 76. The screws 76 having rubberized heads 78 which aid in providing a non sliding mounting surface for the bottom of base member 32.

Various changes in the described canister incubator embodiment may be made without departing from the spirit and scope of this invention without departing from the scope thereof as defined by the ensuing claims.

We claim:

1. Apparatus for the incubation of cultures comprislng:

an inner core tubular rack assembly and an open top tubular canister assembly for holding said tubular rack assembly; said rack assembly having a plurality of horizontally extending shelves for supporting culture plates suspended thereon, and having a cap comprising a top cover plate designed to seal the inside of the canister assembly from the outside environment lwhen the rack assembly is inserted therein,

each of said shelves being of T-shaped configuration with the top of the T of said T-shaped shelf of uniform cross section providing the leading edge over which a culture plate is inserted, and

spring means extending between each of said shelves for retaining culture plates inserted thereon. 2. Apparatus according to claim 1 wherein said top cover plate has a handle member mounted thereon for lifting said core assembly out of said apparatus to remove individual culture plates,

said handle member including a clamping arm pivotally mounted on a pin secured to said handle member and said clamping arm and extending therebetween,

said pin including a spring wound therearound and secured to said handle at one end thereof, the other end of said spring being secured to said clamping arm,

said clamping arm having a central portion and downturned flange portions at opposite ends thereof, said downturned llange portions including inturned flange portions at the ends thereof,

said canister assembly comprising a cylinder supported at the base thereof by a base member containing a ballast member and operating controls including a switch and pilot light for controlling heating power applied to said apparatus,

said cylinder including a lock ring at the top open end thereof,

said lock ring comprising a ange portion extending outwardly from said cylinder and having a locking slot for passage therein of said inturned flange portions of said clamping arm to provide pressure locking of said rack within said canister assembly.

3. Apparatus according to claim 2 wherein said canister assembly includes a sensing platform for insulatively References Cited Scientific Apparatus and Reagents, catalog published 'by Arthur H. Thomas Co., Philadelphia, Pa., 65th edition, page 412 (1965).

ALVIN E. TANENHOLTZ, Primary IExaminer U.S. Cl. X.R. 195-127 

